Lightning-arrester.



" W. GIFFO'RD.

LIGHTNING ARRESTER APPLICATION FILED M2125, 190s.

Patented Apr. 27, 1909.

WILLIAM GIFFORD, OF TRAVERSE CITY, MICHIGAN.

LIG-HTNING-ARRESTER.

Specification of Letters Patent.

Patented April 27', 1909.

Application filed March 25, 1908. Serial No. 423,208.

To all whom it may concern:

Be it known that I, lVILLILmr Gnrronn, a citizen of the United States,residing at Traverse City, in the county of Grand Traverse and State ofMichigan, have invented a new an d useful Lightning-Ariester, of whichthe following is a specification.

This invention relates to lightning arresters of that general classemployed for protecting electrical apparatus and circuits from injury bycharges of static electricity, the present invention being particularlyeffective for street car service where a very sensitive non-arcingarr-ester is required.

The obj ectof the invention is to provide a lightning arrester in whichthe static charge from the line is conducted to the ground by means of abank of high resistance conducting paths, disposed parallel with eachother and each connected in series with an air gap, the resistance ofthe conducting paths being such that the current at line voltage cannotpass the air gap.

A further object of the invention is to provide a multiple dischargearrester that is sensitive in operation and positively nonarcing andnon-inductive, the construction and relative disposition of the severalparts being such as to produce a compact rigid structure having nomoving parts or coils to become short circuited, and which willneutralize all disturbances due to surging and keep the line free fromall static accumulations.

A still further object of the invention is generally to improve thisclass of devices so as to increase their utility, durability andefficiency.

Further objects and advantages will appear in the following description,it being understood that various changes in form, proportions and minordetails of construction may be resorted to within the scope of theappended claims.

In the accompanying drawings forming a part of this specification:Figure 1 is a perspective view of lightning arrester constructed inaccordance with my invention. Fig. 2 is a similar view showing theseveral parts detached. Fig. 3 is a vertical sectional view of Fig. 1.Fig. l is an enlarged detail sectional view. Fig. 5 is a verticalsectional view illustrating a modified form of the invention.

Similar numerals of reference indicate corresponding parts in all of theligures of the drawings.

The improved lightning arrester forming the subject matter of thepresent invention comprises a base 5 formed of marble, slate, porcelainor other insulating material, said base being of any desired size orshape and provided with openings 6 for the reception of screws orsimilar fastening devices 7 by means of which the base may be readily attached to a wall or other suitable support.

Mounted on the exposed face of the base 5 are spaced substantiallyrectangular plates 8 and 9 formed of asbestos board or other lire proofmaterial having good insulating qualities, said plates being preferablytreated with a fire proof filler to render the same non-absorptive. Theinner face of each plate at the top thereof is coated with a layer ofgraphite, carborundum, carbon or other material having a highresistance, and tending from the layer 10 and forming a continuation ofthe same are a plurality of vertical strips 11 also preferably formed bycoating the face of the plates with said material and which constitute abank of high resistance conducting paths for the static charge from theline.

Interposed between the plates 8 and 9 are one or more strips of asbestos12 which may or may not be provided with conducting paths similar to theconducting paths ll, said plates and asbestos strip being rigidlysecured to the base 5 by screws or similar fastening devices 13. Thespacing strip 12 terminates at the layer or coating 10 and disposedbetween the plates at said coating is a metallic distributing bar l lprovided with a binding post 15 for connection with the adjacent end ofthe line wire 16.

Secured to the base 5 beneath the plates 8 and 9 is a transverse raclr17 preferably in the form of a metallic bar having sockets 18 formedtherein for the reception of a plurality of vertically adjustable pins19, said pins being locked in adjusted position by screws or similarfastening devices 20 which extend through the face of the bar 17 andbear against the pins, as shown.

Depending from the bottom of the term inal carrying bar 17 is a bindingpost 21 having a conductor 22 secured thereto for grounding the staticcharge from the line.

The terminals of the pins 19 are disposed in vertical alinement with thefilling or spaclUO ing strip 12 and are spaced from the plates 8 and 9to form an intermediate bank of air or spark gaps 23, the inner faces ofthe plates 8 and 9 being beveled or rounded at 2% and tipped with metalor a coating of carborundum or other material similar to the coatingforming the conducting paths ll. The conducting paths 11 are disposedparallel with each other and in series with the bank of air or sparkgaps 23, the spacing or filling strip 12 serving to keep the staticdischarge divided until it reaches the bar 17.

By forming the conducting paths on the plates 8 and 9 and curving orbeveling the ends of said plates at the pins 19 a double discharge isobtained at each pin, as best shown in Fig. 4 of the drawings.

The upper distributing bar 14L is locked in position by bolts or screws25 which extend through the plates 8 and 9 and also pierce the base 5,there being sockets or countersunk portions formed in the rear face ofthe base to receive the heads of the bolts or screws 13 and 25, asshown.

It will thus be seen that the static charge enters the arrester throughthe binding post 15 and is immediately distributed to the severalconducting paths 11, passing through the same in parallel paths andbringing the bank of spark gaps and thence to the ground. Attention ishere called to the fact that the intermediate strip 12 not only servesto space the plates 8 and 9 so as to maintain the cur\ ed terminals 24of the conducting paths in proper relation to each other and to the pins19, but also assist in preventing accidental displacement of thecompound con stituting the conducting paths and prevent said compoundfrom scaling or disintegratmg.

in Fig. 5 of the drawings there is illustrated a modified form of theinvention especially designed for use in energized circuits having alower voltage than that required for the arrester shown in Fig. 1 of thedrawings. In this form of the device the insulating filler or spacingstrip 12 terminates short of the lower ends of the plates 8 and 9 and isdisposed in spaced relation to a metallic or carbon bar 27 interposedbetween the lower ends of the plates, as shown. The lower bar 27 and theupper distributing bar l i are rigidly combined with the plates andsupporting base by screws or similar fastening devices 28 similar to thefastening devices shown in 3 of the drawings, there being a binding post29 depending from the bar 27 for grounding the discharge from theconducting paths 11. In this form of the device the static charge entersthe binding post 30 where it is distributed by the bar 14 to the severalconducting paths 11, the charge passing down these paths to the space 31between the filling strip 12 and bar 27 where it leaks over the surfaceof the dielectric to the bar 27", the resistance of each conducting pathbeing such that no current at line voltage can flow across the space Theclamping screws 30 of the several binding posts are each fitted withlock nuts 31 which keep the screws from working loose, from vibration orother causes, and thus securely hold the line and ground wires inposition.

lVhile l have described the principle of operation of the inventiontogether with the apparatus which I now consider to be the bestembodiment thereof I desire to have it understood that the constructionshown is merely illustrated and that the invention may be carried out byother means.-

Having thus described the invention what is claimed is:

1. A lightning arrester including a base,

an insulating member secured to the base and having its face coated witha high resistance compound to form a bank of conducting paths disposedparallel with each other and provided with inclined terminals, adistributing bar extending transversely across the conducting paths atone end of the arrester, and a grounded terminal spaced from andco-acting with the inclined ter minals of the conducting paths.

2. A lightning arrester including a base, spaced insulating elementssecured to the base and having their lower edges inclined and theirinner faces provided with a bank of high resistance conducting paths extending to the inclined edges of said insulating elements, an insulatingspacing strip interposed between the insulating elements, a distributingbar connected with the conducting paths, a grounded terminal disposedbeneath the insulating elements, and pins carried by the groundedterminal and disposed between the inclined edges of the insulatingelements.

3. A lightning arrester including a base, spaced insulating elementssecured to the base and having their adjacent faces inclined or beveledat the lower ends of the elements, said elements being provided with aplurality of high resistance conducting paths extending to and coveringthe inclined ends of the insulating elements, an insulating spacingstrip interposed between the insulating elements, a bar disposed beneaththe insulating elements and connected with the ground, and terminalscarried by the bar and spaced from and disposed in alinement with thespacing strip to form a bank of air gaps, the conducting paths beingdisposed parallel with each other and arranged in series with the bankof air gaps.

* a. A lightning arrester including a base, spaced insulating platesmounted on the base and each having its inner face coated with ahiglrresistance compound to form a plurality of conducting paths, aninsulating spacing strip interposed between the plates and terminatingshort of the upper ends thereof to form a recess, a distributing barseated in the recess and connected with the several conducting paths,and a grounded terminal cooperating with and spaced from the conductingpaths.

5. A lightning arrester including a base, spaced insulating platessecured thereto and each provided with a plurality of high resistanceconducting paths, an insulating strip interposed between the plates, adistributing bar connected With the conducting paths, a

grounded bar arranged beneath the insulating plates and having socketsformed therein, vertically adjustable pins seated in said sockets andspaced from the adjacent ends of the plates to form a bank of air gaps,the conducting paths being disposed parallel with each other andarranged in series With the air gaps, and means for locking the pins inadjusted position.

In testimony that I claim the foregoing as my own, I have hereto affixedmy signature in the presence of two Witnesses.

VILLIAM GIFFORD.

lvitnesses C. G. Snnnwoon, lncsm r. lVAGLn Y.

